Method for producing mask blank and method for producing transfer mask

ABSTRACT

To obtain a mask blank capable of suppressing build-ups after removing a resist film on a peripheral edge of a substrate and free of resist residues, even if using any kind of resist. In an unnecessary film removing step of a mask blank manufacturing steps, for removing the unnecessary resist film from a substrate  10  formed with a resist film  13  on a prescribed light-shielding film  12 , the surface of the substrate on the side formed with the resist film  13  is covered with a cover member  30 . First, while the substrate  10  is rotated with a prescribed rotation speed R 1 , the unnecessary resist film is dissolved by a chemical liquid  50 . Next, while the substrate  10  is rotated with a prescribed rotation speed R 2 , the dissolved unnecessary resist film is removed. Further, while the substrate  10  is rotated with a prescribed rotation speed R 3 , the area from which the resist is removed is dried. In such a case, R 1 , R 2 , and R 3  are expressed by (I) R 1 =100 to 500 rpm, (II) R 2 ≧300 rpm, (III) R 1&lt; R 2≦ R 3.

TECHNICAL FIELD

The present invention relates to a manufacturing method of a mask blankfrom which an unnecessary resist film formed on the peripheral edge of asubstrate main surface is removed in a mask blank, which is an originalsubstrate of a transfer mask having a transfer pattern for transferringto a body to be transferred on a substrate, and a manufacturing methodof a transfer mask using the mask blank.

BACKGROUND ART

In a manufacturing step of a mask blank, particularly the mask blank,which is an original substrate of a transfer mask formed with a transferpattern becoming a pattern of an electronic circuit on a substrate,after a resist film is formed on a substrate surface forming the maskblank, the substrate passes through various kinds of processing steps inwhich it is held by a carrying mechanism or inserted/removed into/from asubstrate housing case. At this time, the peripheral edge of thesubstrate forming the mask blank comes into contact with a chuck part ofthe carrying mechanism and a housing groove of the housing case, and theresist film on the peripheral edge of the substrate is peeled to becomea dust generation source. Accordingly, a problem is that the peeledresist adheres to a main surface of the mask blank, resulting in adefect.

Therefore, when manufacturing the mask blank, the substrate is subjectedto processing in such a manner that by spin-coating the resist thereonto form the resist film, and thereafter the resist film on theperipheral edge of the substrate is previously removed. In theprocessing, a chemical liquid by which the resist is dissolved is fed tothe resist on the peripheral edge of the substrate while rotating thesubstrate horizontally around a specified rotation center, and theresist film on the peripheral edge of the substrate is thereby dissolvedand removed.

For example, a technique to remove the unnecessary resist film on theperipheral edge of the substrate includes a method disclosed in PatentDocument 1.

The method of removing the unnecessary films comprising: forming theresist film by the spin-coating method, covering the surface of thesubstrate with a cover member formed with a plurality of fine holes onthe peripheral edge of the substrate (part located in the upper part ofthe unnecessary film to be removed), and feeding the chemical liquid(solvent) by which the resist is dissolved from above this cover member,while the substrate and the cover member are integrally rotated. Thesolvent thus fed is fed to the peripheral edge of the substrate throughthe fine holes, and the resist formed on the peripheral edge of thesubstrate is thereby dissolved and removed.

(Patent Document 1)

Japanese Patent Laid Open No. 2001-259502

DISCLOSURE OF THE INVENTION

However, when dissolving and removing the resist formed on theperipheral edge of the substrate by the unnecessary film removing methoddescribed in Patent document 1, it is found that build-ups are generatedon the sectional face of the resist film, or a resist residue isgenerated according to the kind of the resist. It is also found that theremoved width of the resist film is larger in the corner parts anddifferent along the sides of the substrate, resulting in high variationsin removed width.

Regarding this phenomena, explanation will be given with reference tothe drawings.

FIG. 7 is an enlarged view of an end portion of a mask blank obtainedwhen removing the unnecessary film by the conventional technique.

In FIG. 7, designation mark 11 designates a light-transmittingsubstrate, mark 12 designates a light-shielding film or an opaque film,and mark 13 designates a resist film. Further, mark 13 a designates theunnecessary resist film, mark 13 b designates the build-up part, andmark 13 c designates the resist residue.

As shown in FIG. 7, it is found that after removing the resist film 13 aof the unnecessary film formed on a substrate 11 by a solvent, thebuild-up 13 b is generated or the resist residue 13 c is remained in thesectional face of the resist film remained after removing the resist onthe peripheral edge of the substrate 11. Also, it is found that theabove-described phenomena is observed when the resist film on theperipheral edge of the substrate is removed, while covering the surfaceof the substrate on the side formed with the resist film with a covermember. Particularly, when the build-up 13 b exists as shown in FIG. 7,as described above, the problem is that when inserting/removing the maskblank into/from the substrate housing case, the resist film is peeled tobecome a dust source, or when the area of the build-up 13 b is formedwider toward the center of the substrate 11, a pattern gets blurred whenpatterning an alignment mark, etc., in the vicinity of the peripheraledge of the substrate. In addition, the problem is that when the heightof the build-up 13 b is large, the pattern near the peripheral edge ofthe substrate (for example, the alignment mark or a quality assurancepattern) becomes defective, and therefore in order to prevent thedefective pattern, the resist film requires exposure plural times,thereby complicating a patterning step.

Moreover, in Patent Document 1, the variations in the removed width ofthe resist film are large. The reason is considered such that in aprocess of dissolving and removing the unnecessary resist film by thesolvent, since the substrate has a rectangular shape (rectangular shapeincluding a parallelpiped shape and a square shape), removing force byrotation applied on the dissolved resist is different between the cornerparts of the substrate and the parts other than the corner parts.Therefore, the problem arises such that an auxiliary pattern such as analignment mark near the peripheral edge of the substrate is defectivedepending on circumstances.

However, an exposure light source wavelength such as i beam (365 nm ofwavelength) is longer compared with the beams of today when using thetransfer mask, and the line width variation quantity of the mask patternto be formed is larger compared with that of today. Therefore, theallowable defect decision level is not set so strict, and a mask patternforming area is relatively small. Accordingly, the auxiliary patternsuch as the alignment mark is formed closer to the center from theperipheral edge of the substrate, thereby not particularly involvingproblem regarding the above-described resist residues, build-ups, andvariations in removed width. However, in recent years, as the exposurelight source wavelength is made shorter, the pattern is made finer, andthe mask pattern forming area is made larger, the allowable defectdecision level is set more strict. Also, by forming the auxiliarypattern such as an alignment mark at a part near the side face of thesubstrate, a problem is generated.

Therefore, in view of the above-described circumstances, the presentinvention is provided. A first object of the present invention is toprovide a manufacturing method of a mask blank capable of suppressingvariations in removed width after removing a resist film on theperipheral edge of a substrate even when any kind of resist is used. Asecond object of the present invention is to provide a manufacturingmethod of a mask blank capable of suppressing build-ups, free of resistresidues, further capable of suppressing variations in removed width,after removing the resist film on the peripheral edge of the substrateand thereby preventing the defect caused by re-adhesion of the dissolvedresist. A third object of the present invention is to provide amanufacturing method of a transfer mask free of pattern defectsgenerated in patterns such as an alignment mark and a QA pattern(quality assurance pattern), and an auxiliary pattern such as a bar codepattern formed near the peripheral edge of the substrate.

The present invention requires the following structure, so as to solvethe above-described problems.

(Structure 1) There is provided a manufacturing method of a mask blank,comprising:

-   -   preparing a rectangular-shaped substrate formed with a thin film        becoming a transfer pattern to be transferred to a body to be        transferred, and formed with a resist film by coating a resist        liquid on the thin film and drying it;    -   removing an unnecessary resist film formed in a resin-removed        area provided in the peripheral edge of a main surface of the        substrate by using a chemical liquid;    -   heating the resist film formed in a non-resin-removed area,        which is a main surface of the substrate and an area other than        the resin-removed area;    -   wherein a cover member is fitted to the surface of the substrate        on the side formed with the resist film in a separated state at        a designated distance from the main surface of the substrate in        the resin-removed area, further the substrate is rotated at a        prescribed rotation speed R1, and after dissolving the        unnecessary resist film by feeding the chemical liquid to the        gap, the chemical liquid is stopped to be fed thereto, and        further, the substrate is rotated at a higher revolution than        the prescribed rotation speed, thereby removing the dissolved        unnecessary resist film outside the substrate and drying it,    -   wherein the revolution of the substrate when the dissolved        unnecessary resist film is removed outside the substrate and the        area from which the resist film is removed is dried, is set to        be rotation speed R2 at which the substrate is rotated and the        variations in removed width of each side of the substrate are        suppressed, the variation being caused by the difference in        centrifugal force applied on the dissolved resist film in a        direction along each side of the peripheral edge of the main        surface of the substrate, and thereafter, the substrate is        rotated at a prescribed rotation speed R3 so as to dry the area        from which the resists film is removed.

When the unnecessary resist film dissolved by chemical liquid is removedoutside the substrate and dried, since the substrate has a rectangularshape, the centrifugal force by rotation is larger at the corner partsin the peripheral edge of the main surface of the substrate, andsmallest in the center of each side of the substrate. Accordingly, theremoving speed of the resist film dissolved in the corner parts is madeaccelerated, thereby generating variations in removed width in such away that the removed width is larger in the corner parts, and theremoved width becomes smaller as it is closer to the center of each sidefrom the corner parts. By suppressing the acceleration of the removingspeed of the resist film dissolved in the corner parts, and afterremoving the resist film dissolved to some degree by rotating thesubstrate at a prescribed rotation speed R2 by which the variations inremoved width can be suppressed, by rotating the substrate at aprescribed rotation speed R3 so as to dry the area from which the resistfilm is removed, the mask blank capable of suppressing variations inremoved width is obtained.

(Structure 2) There is provided the manufacturing method of the maskblank according to Structure 1, wherein the resist liquid contains atleast any one of diethylene glycol dimethyl ether, anisole, methylcellosolve acetate, and cyclohexanone as the solvent, and rotationspeeds R1, R2, and R3 are set under the conditions of:R1=100 to 500 rpm  (I)R2≧300 rpm  (π)R1<R2≦R3  (

)

As the resist liquid containing at least any one of diethylene glycoldimethyl ether, anisole, methyl cellosolve acetate, and cyclohexanone asthe solvent, generally high-molecular-weight resist is given as anexample. However, generally the viscosity of the resist (raw liquid) isabove 10 cp (in some cases, above 40 cp), which is a high value, andtherefore it is difficult to be dissolved by chemical liquid (slow indissolving speed). Accordingly, for the chemical liquid to successfullypermeate into every gap without surrendering to the centrifugal force byrotation, the rotation speed R1 of the substrate in the dissolving stepof the high-molecular-weight resist is preferably set to be low comparedwith the resist of structure 4 as will be described later.

However, if the rotation speed R1 of the substrate in the dissolvingstep is set to be too low, the centrifugal force by rotation is weak,thereby allowing the chemical liquid to permeate into the center of thesubstrate to form a swelling part of resist, thus forming the build-upparts. However, if the rotation speed R1 of the substrate is set to betoo high, by surrendering to the centrifugal force by rotation, thechemical liquid can not be successfully permeated into every gap, andtherefore the resist formed on the peripheral edge of the substrate cannot be completely dissolved.

Above-described points are taken into consideration, and when the resistcontains the above-described solvents, the rotation speed R1 of thesubstrate is set to be:R1=100 to 500 rpm.  (I)

In addition, if the rotation speed R2 is set to be too low, thedissolved resist is allowed to permeate into the center of thesubstrate, thereby forming the build-ups by swelling of the resist, orthe dissolved resist remains without being removed outside thesubstrate, thereby forming the resist residue.

Accordingly, when the resist contains the above-describe solvents, therotation speed R2 of the substrate is set to be:R2≧300 rpm.  (π)

In addition, with respect to the rotation speed R1 of the substrate, therotation speed R2 of the substrate, and the rotation speed R3 of thesubstrate, R2 needs to be higher than R1 from a point that the resistdissolved by chemical liquid is not allowed to be kept in the peripheraledge of the substrate, but removed outside the substrate. Also, R3 maybe equal to R2 or more from the point of preventing the dissolved resistremained without being completely removed outside the substrate, frompermeating into the center of the substrate. Therefore, in view of theabove points, the rotation speed R1 of the substrate, the rotation speedR2 of the substrate, and the rotation speed R3 are set to be:R1<R2≦R3  (

)

(Structure 3) There is provided the manufacturing method of the maskblank according to structure 2, wherein the rotation speed R2 is set tobe R2=300 to 600 rpm.

By setting the rotation speed R2 in the above-described range, the maskblank is provided, which is capable of more reducing the variations inremoved width, thereby preventing the dissolved resist from scatteringoutside the substrate, hitting against and rebounding from a cupprovided outside the unnecessary film removing apparatus, therebyre-adhering to the cover member and the substrate, resulting in adefect. (Structure 4) The resist liquid contains at least any one ofpropylene glycol monomethyl ether acetate, propylene glycol monomethylether, and methyl isoamyl ketone as the solvent, and the rotation speedsR1, R2, and R3 are set to be:R1=400 to 800 rpm  (I)R2≧500 rpm  (π)R1<R2≦R3  (

)under which condition, the substrate is rotated.

When the resist liquid contains at least any one of propylene glycolmonomethyl ether acetate, propylene glycol monomethyl ether, and methylisoamyl ketone as the solvent, the viscosity of the resist (raw liquid)is generally set low to be 5 cp or less, and therefore easy to bedissolved by chemical liquid (fast in dissolving speed). Accordingly,even if the centrifugal force by rotation works, the chemical liquid iseasily allowed to permeate into the center of the substrate. Therefore,the rotation speed R1 of the substrate of the resist containing theabove-described solvent is set to be high compared with the resist ofthe structure 3.

Namely, if the rotation speed R1 of the substrate is set to be too low,the centrifugal force by rotation is weak, thereby allowing the chemicalliquid to permeate into the center of the substrate, thereby forming thebuild-ups by swelling of the resist, to form the build-up parts.However, if the rotation speed R1 of the substrate is set to be toohigh, by surrendering to the centrifugal force by rotation, the chemicalliquid can not be successfully permeated into every gap, and thereforethe resist can not be dissolved.

In view of the above-described points, the rotation speed R1 of thesubstrate is set to be:R1=400 to 800 rpm.  (I)

Also, if the rotation speed R2 of the substrate is set to be too low,the dissolved resist is allowed to permeate into the center of thesubstrate, thereby forming the build-ups by swelling of the resist, orthe dissolved resist remains without being removed outside thesubstrate, thereby forming the resist residue.

Accordingly, when the resist contains the above-described solvents, therotation speed R2 of the substrate is set to be:R2≧500 rpm.  (π)

In addition, with respect to the rotation speed R1 of the substrate, therotation speed R2 of the substrate, and the rotation speed R3 of thesubstrate, R2 needs to be larger than R1 from the point that the resistdissolved by chemical liquid is not allowed to be kept in the peripheraledge of the substrate, but removed outside the substrate. Also, R3 maybe equal to R2 or more from the point of preventing the dissolved resistremained without being completely removed outside the substrate, frompermeating into the center of the substrate. Therefore, in view of theabove points, the rotation speed R1 of the substrate, the rotation speedR2 of the substrate, and the rotation speed R3 are set to be:R1<R2≦R3.  (

)

(Structure 5) There is provided the manufacturing method of the maskblank according to structure 4, wherein the rotation speed R2 is set tobe R2=500 to 900 rpm. By setting the rotation speed R2 in theabove-described range, the mask blank is obtained, which is capable ofmore reducing the variations in removed width, thereby preventing thedissolved resist from scattering outside the substrate, hitting againstand rebounding from a cup provided outside the unnecessary film removingapparatus, thereby re-adhering to the cover member and the substrate,resulting in a defect.

(Structure 6) There is provided the manufacturing method of the maskblank according to any one of the structures 2 to 5, wherein therotation speed R3 is equal to 1000 rpm or more, and equal to 3000 rpm orless.

By setting the rotation speed R3 to be equal to 1000 rpm or more, thearea from which the resist film is removed by chemical liquid can bedried quick, thereby improving throughput. Meanwhile, by setting therotation speed R3 to be equal to 3000 rpm or less, the risk that thecover member is detached from the substrate can be avoided.

(Structure 7) There is provided the manufacturing method of the maskblank according to any one of the structures 1 to 6, wherein the gap isset to be the size large enough to allow the chemical liquid to flowthereinto through the gap and kept in the gap.

In the removed area of the main surface of the substrate, the gap formedbetween the cover member and the main surface of the substrate is set tobe the size large enough to allow the chemical liquid to flow into thegap through the gap and kept only in the gap. With this structure, by anaction of the surface tension of the chemical liquid, and an action ofthe centrifugal force by rotation of the substrate, the chemical liquidcan be surely and exactly fed to a prescribed part of the main surfaceof the substrate.

(Structure 8) There is provided the manufacturing method of the maskblank according to any one of the structures 1 to 7, wherein the covermember covers the main surface formed with a space larger than the gap,in the non-resin-removed area other than the resin-removed area.

With this structure that cover member covers the main surface of thesubstrate, the thermal influence on the resist film by air current fromthe upside of the substrate can be prevented, and further by forming thespace in the non-resin-removed area larger than the gap in theresin-removed area, the invasion of the chemical liquid into thenon-resin-removed area can be prevented.

(Structure 9) There is provide the manufacturing method of the maskblank according to any one of the structures 1 to 8, wherein thechemical liquid is fed from the upside of the cover member, and fed tothe unnecessary resist through the chemical liquid flowing path providedin the cover member.

Thus, by feeding the chemical liquid from the upside of the cover memberto the unnecessary resist through the chemical liquid flowing pathprovided in the cover member, the unnecessary resist film can beremoved, while the consumption of the chemical liquid is suppressed.

(Structure 10) There is provided the manufacturing method of the maskblank according to any one of the structures 1 to 9, wherein thechemical liquid feeding path for feeding the chemical liquid is providedin a position corresponding to the unnecessary resist film portion inthe cover member, or a chemical liquid guide member is provided outsidethe cover member, and the chemical liquid flowing path is set to bebetween the cover member and the chemical liquid guide member.

Thus, by providing the chemical liquid feeding path for feeding thechemical liquid in the position corresponding to the unnecessary resistfilm portion, or providing the chemical liquid guide member outside thecover member, thereby setting the chemical liquid flowing path betweenthe cover member and the chemical liquid guide member, the chemicalliquid can be precisely fed to the unnecessary resist film portion, andtherefore the removed area of the resist film can be strictlycontrolled.

(Structure 11) There is provided a manufacturing method of a transfermask, wherein by using the mask blank obtained by the manufacturingmethod of the mask blank according to any one of the structures 1 to 10,the thin film is patterned to form a transfer pattern on the substrate.

By preparing the transfer mask using the mask blank obtained by themanufacturing method of the mask blank according to the structures 1 to10, a good transfer pattern can be obtained, which is free of a patterndefect in the pattern formed in the peripheral edge of the substratesuch as an alignment mark, QA pattern (quality assurance pattern), and abar code pattern, caused by the build-ups after removing the resistfilm.

BRIEF DESCTIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view showing the structure of an unnecessaryfilm removing apparatus used in an unnecessary film removing steprelating to an embodiment.

FIG. 2 is a partially enlarged sectional view of FIG. 1.

FIG. 3 is a partially enlarged sectional view of FIG. 1.

FIG. 4 is an exploded perspective view of the unnecessary film removingapparatus used in the unnecessary film removing step relating to theembodiment.

FIG. 5 is a graph showing a change in time of the rotation speed of thesubstrate relating to the embodiment.

FIG. 6 is a graph showing the change in time of the rotation speed ofthe substrate in other applied example.

FIG. 7 is an enlarged view of an end portion of a mask blank obtainedwhen the unnecessary film is removed by the conventional technique.

-   10 Substrate (mask blank)-   11 (Transparent) substrate-   12 Resist film-   13 a Unnecessary film-   20 Turn table-   21 Cover member-   40 Nozzle-   50 Chemical liquid-   60 Thread

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be explained withreference to the drawings hereunder. FIG. 1 is a side sectional viewshowing the structure of an unnecessary film removing apparatus used inan unnecessary film removing step relating to an embodiment. FIG. 2 andFIG. 3 are partially enlarged sectional views of FIG. 1. FIG. 4 is anexploded perspective view of the unnecessary film removing apparatusused in the unnecessary film removing step relating to the embodiment.FIG. 5 is a graph showing the change in time of the rotation speed of asubstrate relating to the embodiment, where the times are shown on thehorizontal axis, and the rotation speed is shown on the vertical axis.

In FIG. 1 to FIG. 4, a substrate 10 is a mask blank in which alight-shielding film 12 formed of chrome is formed on the surface of alight-transmitting substrate (152.4 mm×152.4 mm×6.35 mm) 11 formed ofsynthetic quartz glass, and further on the light-shielding film 12, anunbaked resist film 13 of 4000 angstrom thickness is formed by aspin-coating method.

An upper surface side of the substrate 10 placed and held on a turntable20 is covered by a cover member 30, and chemical liquid 50 thatdissolves the resist film by a nozzle 40 from the upside of the covermember is ejected and fed to an unnecessary film part 13 a through achemical liquid feeding hole of the cover member 30, thereby dissolvingthe unnecessary part 13 a.

The cover member 30 covers the substrate 10 in such a manner as to coverthe substrate 10 from the upside, and a major part raging from thecenter to the peripheral edge is a flat section 32. An inclined section33 is formed from the flat section 32 to the outer peripheral section,and from the inclined section 33 to further the outer peripheralsection, a peripheral flat section 34 is formed. The outer peripheraledge of the peripheral flat section 34 is bent at an approximately rightangle, and a side surface section 35 is formed.

In the peripheral flat section 34, chemical liquid feeding holes 31,which are a plurality of through holes, are formed. Regarding thechemical liquid feeding holes 31, suitable shape, size and forming gapare selected according to the viscosity, etc., of chemical liquid 50.Namely, a hole shape may be a square, a rectangle, a circular shape, anelliptical shape, and any other shape. The size of the hole is set to belarge enough to allow the chemical liquid to be evenly fed to theunnecessary film 13 a at a fixed feeding speed. In addition, theinterval between each hole is set so that the chemical liquid fed fromthe chemical liquid feeding holes can spread all over the unnecessaryfilm 13 a without spacing.

The area on the substrate surface opposing to the inner wall of the flatsection 32, which occupies a major part ranging from the center of thecover member 30 to the peripheral edge, is the area (area other than theunnecessary film 13 a) of the necessary film 13. In this area, the gapbetween the inner wall of the cover member 30 and the surface of thesubstrate 10 is set to be larger than d1 as will be described later, sothat the surface tension caused by chemical liquid does not work betweenthe substrate surface and the cover member, and the gap is sized largerthan the specified size, so that the temperature distribution of theresist film 13 may not be affected by heat transfer from the inner wallof the cover member 30, and in addition, the gap is sized smaller thanthe specified size, so that the temperature distribution is notgenerated in the resist film 13 on the main surface of the substrate byconvection of gas which is generated in the gap.

As shown in FIG. 1 and FIG. 2, the size of the gaps is set by putting athread 60 (for example, resin-based substance) having resistance tochemical liquid through several suitable parts of the chemical liquidfeeding holes 31, so as to be interposed between the inner wall of thecover member 30 and the surface of the substrate 10, to set the size ofthe gaps. Specifically, the thread 60 passes through the chemical liquidfeeding holes 31, passes between the inner wall of the peripheral flatsection 34 and the surface of the substrate 10, and passes between theinner wall of the side surface section 35 and the side surface of thesubstrate 10, and further passes outside the side surface section 35 ofthe cover member 30, thereby forming the shape of loop.

The thickness of the thread 60 is set to be the size allowing thechemical liquid to be spread into the gap through the gap by the surfacetension of the chemical liquid and the centrifugal force of thesubstrate, when feeding the chemical liquid into the gap d1 between theinner wall of the peripheral flat section 34 and the main surface of thesubstrate 10.

In addition, the size of the gap d2 between the inner wall of the sidesurface section 35 and the side surface of the substrate 10 may be thesize allowing the chemical liquid to pass through while contacting theresist film.

Moreover, as shown in FIG. 1 and FIG. 3, a chemical liquid feedingnozzle 40 a is provided under the substrate 10 also, and by feedingchemical liquid 50 a from the nozzle 40 a, the unnecessary resist film13 a can be surely removed.

In addition, regarding a turntable 20, a rotation axis 21, support arms22, and holding pedestals 23, explanation will be given by using FIG. 4.

Based on FIG. 4, an appearance in which the substrate 10 is held by theturntable 20 will be explained. The substrate 10 is held by theturntable 20 by having arranged therein four support arms 22 attached tothe rotation axis 21 and extended radially to the horizontal direction,and four corners of the substrate 1 on the holding pedestals 23 having apair of holding pedestals 23 provided on the tip part of each supportarm 22. The rotation axis 21 is connected to a rotation driving devicenot shown, and is rotated by a predetermined rotational frequency. Thesubstrate 10 covered by the cover member 30 is held by the turntable 20and processed while rotating. Note that signs and numerals used forexplanation in FIGS. 1 to 3 are the same sings and numerals used foreach part shown in FIG. 4.

Next, explanation will be given to an embodiment capable ofmanufacturing the mask blank without resist residues by suppressing thebuild-ups after removing the resist film on the peripheral edge of thesubstrate, even when using various kinds of resists.

(In a Case of a High-Molecular-Weight Resist)

The resist liquid of a high-molecular-weight resist contains at leastone type of solvent selected from the group consisting of diethyleneglycol dimethyl ether, anisole, methyl cellosolve acetate, andcyclohexanone as the solvent, the viscosity (raw liquid) of the resistis high to be set to be above 10 cp (above 40 cp sometimes), andtherefore, it is difficult to be dissolved by the chemical liquid (slowin dissolving speed). Accordingly, for the chemical liquid tosuccessfully permeate into every gap without surrendering to thecentrifugal force by rotation, the rotation speed R1 of the substrate ispreferably set to be low so as to allow the chemical liquid tosuccessfully permeate into every gap.

However, if the rotation speed R1 of the substrate is set to be too low,the centrifugal force by rotation is weak, thereby allowing the chemicalliquid to be permeated into the center of the substrate to form aswelling part in the resist, thus forming the build-up parts. However,if the rotation speed R1 of the substrate is set to be too high, bysurrendering to the centrifugal force by rotation, the chemical liquidcan not be successfully permeated into every gap, and therefore theresist formed on the peripheral edge of the substrate can not becompletely dissolved.

Above-described points are taken into consideration, and the rotationspeed R1 of the substrate in the resists containing the above-describedsolvents is preferably set to be:(I) R1=100 to 500 rpm.

In addition, rotation time T1 of the substrate is a time till the resistis dissolved by the chemical liquid. T1 is preferably set to be 20 secor more, and further preferably set to be 20 to 45 sec. If the time T1is longer, although the resist residues are not generated, deteriorationin throughput is not prevented, and further the sectional surface of theresist film after removing the resist on the peripheral edge of thesubstrate is exposed to chemical liquid for a long time, thus notpreferably forming build-ups by swelling of the resist.

Moreover, if the rotation speed R2 is set to be too low, the dissolvedresist is allowed to permeate into the center of the substrate, therebyforming the build-ups by swelling of the resist, or the dissolved resistremains without being removed outside the substrate, thereby forming theresist residues.

Accordingly, the rotation speed R2 of the substrate in the resistcontaining the above-described solvents is preferably set to be:R2≧300 rpm.  (π)In addition, from the viewpoint of preventing the dissolved resist fromscattering outside the substrate, hitting against and rebounding from acup provided outside the unnecessary film removing apparatus, therebyre-adhering to the cover member and the substrate, resulting in adefect, the rotation speed R2 of the substrate is preferably set to be1000 rpm or less.

Further, from the viewpoint of reducing the variations in removed widthin each side of the substrate caused by the difference in centrifugalforce by rotation of the dissolved resist in a direction along each sideof the peripheral edge of the main surface of the substrate, andpreventing the defects caused thereby, the rotation speed R2 ispreferably set to be R2=300 to 600 rpm.

Moreover, the rotation time T2 of the substrate is the time till thedissolved resist on the peripheral edge of the substrate is completelyremoved outside the substrate, and T2 is preferably set to be 10 sec ormore.

If T2 is set to be too long, although the resist residues are notgenerated, the throughput is thereby deteriorated. Therefore T2 ispreferably set to be 25 sec or less.

In addition, from the viewpoint that the rotation speed R3 of thesubstrate allows the resist dissolved by chemical liquid to be removedoutside the substrate, without allowing it to be kept in the peripheraledge of the substrate, R2 must be set to be higher than R1. Also, fromthe viewpoint of preventing the resist not completely removed outsidethe substrate and remained, from permeating into the center of thesubstrate, R3 may be more than R2.

Therefore, the above-described viewpoints are taken into consideration,the rotation speed R1 of the substrate, the rotation speed R2 of thesubstrate, and the rotation speed R3 of the substrate are preferably setto be:R1<R2≦R3.  (

)

Further, the rotation speed R3 of the substrate is preferably set to be1000 rpm or more, so as to easily dry the area from which the resist isremoved. However, if the rotation speed is set to be too high, with thecover member just covering the substrate and not fixing it, the covermember is possibly detached. Accordingly, the rotation speed ispreferably set to be 3000 rpm or less, from the point of safety.

In addition, the rotation time T3 is the time required for completelydrying the removed area on the peripheral edge of the substrate, and T3is preferably set to be 30 sec or more.

(In a Case of the Resist Other Than High-Molecular-Weight Resist)

When the resist liquid contains at least one type of solvent selectedfrom the group consisting of propylene glycol monomethyl ether acetate,propylene glycol monomethyl ether, methyl isoamyl ketone as a solvent,viscosity of the resist (raw material) is generally set to be low, to be5 cp or less, and therefore such a resist liquid is easily dissolved bychemical liquid, compared with the above-described high-molecular-weightresist (fast in dissolving speed). Accordingly, even if the centrifugalforce by rotation works, the chemical liquid easily permeates into thecenter of the substrate of the gap. Therefore the chemical liquidsuccessfully permeates into every gap, and the rotation speed R1 of thesubstrate is adjusted so that the chemical liquid may not permeate intothe center of the substrate.

Specifically, if the rotation speed R1 of the substrate is set to be toolow, the centrifugal force by rotation is weak, therefore the chemicalliquid permeates into the center of the substrate, and build-ups areformed by swelling of the resist. However, if the rotation speed R1 isset to be too high, by surrendering to the centrifugal force byrotation, the chemical liquid can not successfully permeate into thegap, and therefore the resist can not be successfully dissolved.

The above-described points are taken into consideration, and therotation speed R1 of the substrate in the resist containing theabove-described solvents is preferably set to be:R1=400 to 800 rpm.  (I)

Also, the rotation time T1 of the substrate is the time required fordissolving the resist by chemical liquid, and T1 is preferably set to be5 sec or more, and further preferably set to be 5 to 25 sec. If T1 isset to be too long, although the resist residues are not generated,deterioration in throughput is not prevented, and further the sectionalsurface of the resist film after the resist on the peripheral edge ofthe substrate is removed is exposed to chemical liquid for a long time,thus not preferably forming build-ups by swelling of the resist.

In addition, if the rotation speed R2 of the substrate is set to be toolow, the dissolved resist permeates into the center of the substrate,and therefore build-ups are formed by swelling of the resist, or thedissolved resist is remained without being removed outside thesubstrate, thereby forming resist residues.

Accordingly, the rotation speed R2 of the substrate in the resistcontaining the above-described solvents is preferably set to be:R2=500 rpm.  (π)

In addition, the rotation speed R2 is preferably set to be 1000 rpm orless, from the point of preventing the dissolved resist from scatteringtoward outside the substrate, hitting against and rebounding from thecup provided in the outside the unnecessary film removing apparatus, andthereby re-adhering to the cover member and the substrate.

Further, the rotation speed R2 is preferably set to be R2=500 to 900rpm, from the point of reducing the variations in removed width in eachside of the substrate caused by the difference in the centrifugal forceby rotation of the dissolved resist film in a direction along each sideof the peripheral edge of the main surface of the substrate, and therebypreventing the defect caused by the peeled resist.

Also, the rotation time T2 of the substrate is the time required forcompletely removing the dissolved resist on the peripheral edge or thesubstrate outside the substrate, and T2 is preferably set to be 3 sec ormore.

If the time of T2 is set to be too long, although the resist residuesare not generated, the deterioration in throughput is invited, andtherefore, T2 is preferably set to be 20 sec or less.

Also, regarding the rotation speed R1 of the substrate, the rotationspeed R2 of the substrate, and the rotation speed R3 of the substrate,R2 must be larger than R1, from the point of removing the dissolvedresist by chemical liquid outside the substrate without allowing it tobe kept in the peripheral edge of the substrate. In addition, R3 may beequal to R2 or more, from the point of preventing the dissolved resistremained without completely being removed outside the substrate, frompermeating into the center of the substrate. Therefore, theabove-described points are taken into consideration, and the rotationspeed R1 of the substrate, the rotation speed R2 of the substrate, andthe rotation speed R3 of the substrate are preferably set to be:R1<R2≦R3.  (

)

Further, the rotation speed R3 of the substrate is preferably set to be1000 rpm or more so as to easily dry the resist-removed area. If therotation speed is raised too high, with the cover member just coveringthe substrate and not fixing it, the cover member is possibly detached.Accordingly, from the point of safety, the rotation speed is preferablyset to be 3000 rpm or less.

In addition, the rotation time T3 is the time required for completelydrying the removed area on the peripheral edge of the substrate, andtherefore T3 is preferably set to be 20 sec or more.

(Common Feature Between High-Molecular-Weight Resist and the OtherResist)

The gap formed between the cover member and the main surface of thesubstrate in the resist-removed area of the main surface of thesubstrate, is preferably set to be the size allowing the chemical liquidto flow into the gap through the gap and kept only in the gap. Thus, bythe action of the surface tension of the chemical liquid and thecentrifugal force by rotation of the substrate, the chemical liquid canbe surely and correctly fed to a prescribed part of the main surface ofthe substrate. The gap is set to be the size within a range from 0.05 mmto 3 mm. If the size of the gap is under 0.05 mm or beyond 3 mm, itbecomes difficult for the chemical liquid to be spread into the gapthrough the gap, thereby forming a part that can not be removed orforming nicks at the boundary between the removed part and the otherpart.

Therefore, by using the mask blank obtained by the above-describedmanufacturing method of the mask blank and thereby preparing thetransfer mask, there can be obtained a good transfer pattern withoutpattern defects caused by the build-ups after removing the resist filmin the pattern formed on the peripheral edge of the substrate such as analignment mark, QA pattern (quality assurance pattern), and a bar codepattern.

(Example of a High-Molecular-Weight Resist)

As the resist containing at least one type of solvent selected from thegroup consisting of diethylene glycol dimethyl ether, anisole, methylcellosolve acetate, and cyclohexanone as the solvent, generally thehigh-molecular-weight resist is given as an example. The resist whosemolecular weight is within a range from several ten thousands to severalhundred thousands is referred to as the high-molecular-weight resist. Asthe resist available on the market, ZEP series (produced by NIPPONZEON), PBS series (produced by CHISSO), EBR series (produced by TORAYIND INC), and OEBR series (produced by TOKYO OHKA KOGYO CO LTD) aregiven as examples.

(Example of the Resist Other than High-Molecular-Weight Resist)

As the resist containing at least one type of solvent selected from thegroup consisting of propylene glycol monomethyl ether acetate, propyleneglycol monomethyl ether, and methyl isoamyl ketone as the solvent, achemically liquidly amplified resist is given as a typical example. Asthe chemically liquidly amplified resist, which is available on themarket, FEP series (produced by FUJIFILM ARCH), NEB series (produced bySiplay Co. Ltd), and AZ series (produced by Hoechst A.G.) are given asexamples.

(Chemical Liquid Path and an Example of Chemical Liquid)

Moreover, as the above-described chemical liquid path, chemical liquidfeeding holes for feeding chemical liquid may be formed in a positioncorresponding to the unnecessary resist film in the cover member toselect it as the chemical liquid feeding path. In addition, as thechemical liquid path, a chemical liquid guide member may be formedoutside the cover member to select the chemical liquid feeding pathbetween the cover member and the chemical liquid guide member.

Further, the chemical liquid may be anything, provided that the resistcan be dissolved thereinto. For example, it is possible to use thesolvents such as ketone, ester, aromatic hydrocarbon, halogenatedhydrocarbon, and ether, into which the resist can be dissolved. Inaddition, in an alkali developing type resist, an alkali developingliquid can be used as a chemical liquid.

(Mask Blank)

The mask blank specified in the present invention refers to either of atransmission type mask blank or a reflective mask blank. In the abovemask blanks, the thin film becoming a transfer pattern to be transferredto a body to be transferred and the resist film are formed on thesubstrate.

The transmission type mask blank is a photo mask blank using alight-transmission type substrate for the substrate, and using a thinfilm by which an optical change is made to the exposure light (forexample, the thin film having a light-shielding function) used whentransferring to the body to be transferred, for the thin film becomingthe transfer pattern. Here, the thin film that makes optical change tothe exposure light means the light-shielding film that shields theexposure light, and a phase shifting film that changes the phasedifference of the exposure light.

Also, the thin film having the light-shielding function includes ahalftone film having the light-shielding function and the phase shiftingfunction.

Accordingly, the transmission type mask blank includes a photo maskblank formed with the light-shielding film, a halftone phase shiftingmask blank formed with the halftone film, and a phase shifting maskblank formed with the phase shifting film.

In addition, the reflective mask blank is a mask blank in which a lowexpansion substrate is used as a substrate, and on the substrate, alight-reflecting multiple layer film and a light absorbing film becomingthe transfer pattern are formed.

In addition, in the mask blank, other than the above-described films,the films such as a resist bottom anti-reflective film (BARC: BottomAnti-Reflective Coating), a resist top anti-reflective film (TARL: TopAnti-Reflective Layer), a resist top protective film, and a conductivefilm may be formed.

Hereunder, embodiments of the manufacturing method of the mask blankusing the above-described unnecessary film removing apparatus will beexplained with reference to FIG. 5.

Moreover, in the embodiments, tables 1 and 2 show the rotation speed androtation time in each step of dissolving, removing, and drying steps,and evaluation results of resist residues and build-ups after executingeach step. Note that in the table 1 and the table 2, “∘” in a resistresidue section shows that no resist residues could be checked in theremove-area of the resist film by observation using a microscope, and“x” shows that the resist residues could be checked. Also, “∘” in abuild-up section shows that no pattern defect could be checked whenmeasuring the sectional surface of the removed resist film 13 with theabove-described tracer type film thickness measuring apparatus andmanufacturing the transfer mask thereafter, and “x” shows that thepattern defect could be checked. Note that the pattern defect wasgenerated when the measurement result showed the maximum film thicknessbeyond 15000 angstrom.

Incidentally, in the following embodiments, for simplifying theexplanation, the dissolving step refers to the step in which thefunction to dissolve is large, the removing step refers to the step inwhich the function to remove the dissolved resist film outside thesubstrate by rotation of the substrate, and the drying step refers tothe step in which the function to dry the removed area is large.However, each of the above-described steps includes the case in whichother function works.

Embodiment 1

In this embodiment, methyl cellosolve acetate (MCA) was used as theresist liquid to be applied on the thin film by usinghigh-molecular-weight resist containing MCA (PBS: produced by CHISSO) asa solvent, and MCA was used as chemical liquid.

First, the substrate 10 is set on the turntable 20 and covered with thecover member 30, and then the chemical liquid 50 is fed thereto from thenozzle 40 while adjusting the feeding amount. At the same time, theturntable 20 is rotated with rotation speed R1 set at 250 rpm androtation time T1 set at 30 seconds. Thus, the chemical liquid 50permeates into the unnecessary film 13 a through the chemical liquidfeeding holes 31 to thereby dissolve the unnecessary film 13 a.(dissolving step)

Next, feeding of the chemical liquid 50 from the nozzle 40 is stopped,and the turntable 20 is rotated with rotation speed R2 set at 450 rpmand rotation time T2 set at 20 seconds. Thus, the unnecessary film ofthe dissolved resist is removed outside the substrate. (removing step)

Next, the turntable 20 is rotated with the rotation speed R3 set at 1000rpm and rotation time set at 40 seconds. Thus, the area from which theunnecessary film 13 a is removed is dried.

(Drying Step)

Next, the substrate 10 is taken out of the unnecessary film removingapparatus, then subjected to heat treatment (baking treatment) tothereby obtain the mask blank having resist film from which the resistfilm 13 is removed. Note that the removed width of the resist film ofthe main surface of the substrate on the side formed with thelight-shielding film is within 1.5 mm±0.3 mm, and variations in theremoved width is small to form a uniform width. The average thickness ofthe resist film was a little less than about 4000 angstrom.

The area from which the resist film was removed was checked by anelectron microscope, to confirm a good condition without resistresidues.

In addition, the sectional face of the resist film 13 thus removed wasmeasured by using the stylus type film thickness measuring apparatus(produced by TAYLOR HOBSON LTD), to confirm about 4500 angstrom maximumfilm thickness and about 500 angstrom build-up. When the transfer maskis prepared by using the mask blank thus formed, defects in patternscaused by the build-ups of the resist film 13 and defects caused bygeneration of dust did not occur. The aforementioned results are shownin table 1.

Embodiments 2 to 3, and Comparative Examples 1 to 5

In table 1, the rotation speed and rotation time are defined as R2 andT1 respectively in the dissolving step, and the rotation speed androtation time are defined as R3 and T3 respectively in the drying step.Other conditions are set same as the embodiment 1, to form a mask blank.TABLE 1 DISSOLVING STEP REMOVING STEP DRYING STEP ROTATION ROTATIONROTATION ROTATION ROTATION ROTATION SPEED R1 TIME T1 SPEED R2 TIME T2SPEED R3 TIME T3 RESIST (rpm) (Sec) (rpm) (Sec) (rpm) (Sec) RESIDUESBUILD-UPS EMBODIMENT 1 250 30 450 20 1000 40 ◯ ◯ EMBODIMENT 2 100 20 30025 1000 60 ◯ ◯ EMBODIMENT 3 500 45 1000 8 1200 30 ◯ ◯ COMPARATIVE 80 15300 25 1000 60 ◯ X EXAMPLE 1 COMPARATIVE 520 60 300 25 1000 60 X ◯EXAMPLE 2 COMPARATIVE 250 30 280 40 1000 60 X X EXAMPLE 3 COMPARATIVE250 30 250 60 1000 60 X X EXAMPLE 4 COMPARATIVE 250 30 300 25 250 >90 XX EXAMPLE 5

As shown in table 1, in the dissolving step of the unnecessary film, theembodiments 1 to 3 revealed a good transfer pattern, in which therotation speed of the substrate in the dissolving step, the removingstep, and the drying step was within the scope of the present invention,without having no resist residues generated and confirming no patterndefects due to the build-ups of the sectional surface of the resistfilm.

Meanwhile, the comparative example 1 revealed a defective pattern, inwhich chemical liquid permeated into the inside of the gap formedbetween the cover member and the main surface of the substrate(unnecessary film 13 a) due to low rotation speed R1 of the substrate inthe dissolving step, thereby enlarging the build-ups of the sectionalsurface of the resist film.

In addition, the comparative example 2 revealed resist residuesgenerated, in which the chemical liquid did not successfully permeateinto the gap formed between the cover member and the main surface of thesubstrate (unnecessary film 13 a) due to high rotation speed R1 in thedissolving step.

Further, the comparative examples 3 and 4 revealed a defective pattern,in which the resist dissolved in the dissolving step was not quicklyremoved and remained, thereby generating resist residues and enlargingthe build-ups of the sectional surface of the resist film.

Moreover, the comparative example 5 revealed a defective pattern withnot large build-ups of the sectional surface of the resist film, inwhich the rotation speed R3 of the substrate in the drying step waslower than the rotation speed R2 of the substrate in the removing step,and therefore the resist remained without being completely removedoutside the substrate permeated into the inside of the substrate andfurther remained without being removed outside the substrate to generatethe resist residues.

Embodiments 4 to 6, Comparative Examples 6 to 10

As for the resist liquid to be applied on the thin film, this embodimentused a chemical amplification type resist (FEP171: produced by FUJIFILMARCH) containing propylene glycol monomethyl ether acetate (PGMEA) andpropylene glycol monomethyl ether (PGME) as a solvent, and also usedmixed solution of PGMEA (propylene glycol monomethyl ether acetate) andPGME (propylene glycol monomethyl ether) as a chemical liquid.

Then, the mask blank was manufactured in the same way as the embodiment1, other than the rotation speed R1 and the rotation time T1 in thedissolving step, the rotation speed R2 and the rotation time T2 in theremoving step, and the rotation speed R3 and the rotation time T3 in thedrying step, which were specified as conditions shown in table 2. TABLE2 DISSOLVING STEP REMOVING STEP DRYING STEP ROTATION ROTATION ROTATIONROTATION ROTATION ROTATION SPEED R1 TIME T1 SPEED R2 TIME T2 SPEED R3TIME T3 RESIST (rpm) (Sec) (rpm) (Sec) (rpm) (Sec) RESIDUES BUILD-UPSEMBODIMENT 4 500 15 750 10 1500 25 ◯ ◯ EMBODIMENT 5 400 5 500 20 1200 30◯ ◯ EMBODIMENT 6 800 20 1000 5 1000 40 ◯ ◯ COMPARATIVE 380 5 500 20 120030 ◯ X EXAMPLE 6 COMPARATIVE 820 30 500 20 1200 30 X ◯ EXAMPLE 7COMPARATIVE 400 5 480 30 1200 30 X X EXAMPLE 8 COMPARATIVE 500 15 500 351200 30 X X EXAMPLE 9 COMPARATIVE 400 15 500 20 400 >60 X X EXAMPLE 10

As shown in table 2, in the unnecessary film removing step, theembodiments 4 to 6, in which the rotation speed of the substrate in thedissolving step, the removing step, and the drying step was within thescope of the present invention, revealed the good transfer patternwithout having the resist residues generated and confirming thedefective pattern due to the build-ups of the sectional surface of theresist.

Meanwhile, the comparative example 6 revealed the defective pattern, inwhich the chemical liquid permeated into the inside of the gap formedbetween the cover member and the main surface of the substrate(unnecessary film 13 a) due to low rotation speed R1 of the substrate inthe dissolving step, thereby enlarging the build-ups of the sectionalsurface of the resist.

Further, the comparative example 7 revealed the resist residuesgenerated, in which the chemical liquid did not successfully permeateinto the gap formed between the cover member and the main surface of thesubstrate (unnecessary film 13 a) due to the high rotation speed R1 inthe dissolving step, thereby generating the resist residues.

In addition, the comparative examples 8 and 9 revealed the defectivepattern, in which the resist dissolved in the dissolving step wasremained without being quickly removed outside the substrate due to thelow rotation speed R2 of the substrate in the removing step, to generatethe resist residues and enlarge the build-ups of the sectional surfaceof the resist film.

Moreover, the comparative example 10 revealed the defective pattern, inwhich the rotation speed R3 of the substrate in the drying step waslower than the rotation speed R2 of the substrate in the removing stepand therefore the resist dissolved and remained without being completelyremoved outside the substrate permeated into the inside of the substrateand remained without being removed outside the substrate, with not largebuild-ups of the sectional surface of the resist film.

Next, relation between the rotation speed R2, variations in the removedwidth, and existence of defects due to re-adhesion of the dissolvedresist was examined.

Embodiments 7 and 8

In the embodiment 1, the mask blank was manufactured in the same way asthe embodiment 1, other than setting the rotation speed R1 to 300 rpm,setting the rotation time T1 to 35 seconds in the dissolving step,setting the rotation speed R2 to 600 rpm, setting the rotation time T2to 15 seconds in the removing step, and setting the rotation speed R3 to1200 rpm, and setting the rotation time T3 to 40 seconds in the dryingstep (Embodiment 7).

In addition, the mask blank was manufactured in the same way as theembodiment 4 other than setting the rotation speed R1 to 600 rpm,setting the rotation time T1 to 15 seconds in the dissolving step,setting the rotation speed R2 to 900 rpm, setting the rotation time t2to 10 seconds in the removing step, and setting the rotation speed R3 to1800 rpm, setting the rotation time T3 to 20 seconds in the drying step(Embodiment 8).

When the variations in removed width of the resist film was examined forthe embodiments 1, 2, 3, and 7, in the case of using the aforementionedhigh-molecular-weight resist, the variations were within 1.5±0.3 mm, tofind uniform removed width with small variations. Further, in theembodiment 3, since the rotation speed R2 was high, the removed width inthe corner part of the substrate became larger to be 1.0 (minimumremoved width) to 2.0 mm (maximum removed width) (1.5±0.5 mm). Also, thedefect-inspecting apparatus did not find the defect due to re-adhesionof the resist on the surface of the substrate.

When the variations in removed width of the resist film was examined forthe embodiments 4, 5, 6, and 8, in the case of using the aforementionedchemical amplification resist, the variations were within 1.5±0.3 mm, tofind the uniform removed width with small variations. Further, in theembodiment 6, since the rotation speed R2 was high, the removed width inthe corner part of the substrate became larger to be 0.8 (minimumremoved width) to 2.2 mm (maximum removed width) (1.5±0.7 mm). Also, thedefect-inspecting apparatus did not find the defect due to there-adhesion of the resist on the surface of the substrate.

Effects shown in the aforementioned embodiments could also be confirmedin ZEP series (produced by NIPPON ZEON), EBR series (produced by TORAYIND INC), OEBR series (produced by TOKYO OHKA KOGYO CO LTD), which arehigh-molecular-weight resists containing at least one type of solventselected from the group consisting of diethylene glycol dimethyl ether,anisole, methyl cellosolve acetate, and cyclohexanone as the solvent,and also in NEB series (produced by Siplay Co. Ltd), SAL series(produced by Siplay Co. Ltd), AZ series (produced by HOECHST), which areresists containing at least one type of solvent selected from propyleneglycol monomethyl ether acetate, propylene glycol monomethyl ether, andmethyl isoamyl ketone as the solvent.

From the aforementioned results, the rotation speeds R1, R2, and R3 ofthe substrate in the dissolving step, the removing step, and the dryingstep of the unnecessary film removing steps were set to be R1=100 to 500rpm, R2≧300 rpm, satisfying R1<R2≦R3, in the case of using the resistcontaining at least one type of solvent selected from the groupconsisting of diethylene glycol dimethyl ether, anisole, methylcellosolve acetate, and cyclohexanone as the solvent. Meanwhile, therotation speeds R1, R2, and R3 were set to be R1=400 to 800 rpm, R2≧500rpm, satisfying R1<R2≦R3 in the case of using the resist containing atleast one type of solvents selected from propylene glycol monomethylether acetate, propylene glycol monomethyl ether, and methyl isoamylketone as the solvent. Whereby, the build-ups generated after removingthe resist film on the peripheral edge of the substrate could besuppressed and also the mask blank without resist residues could beobtained, and further the transfer mask without defective patterns couldbe obtained.

Further, in the case of using the resist including any one of the resistcontaining at least one type of solvent selected from the groupconsisting of diethylene glycol dimethyl ether, anisole, methylcellosolve acetate, and cyclohexanone, by setting the rotation speed R2so as to satisfy the equation, R2=300 to 600 rpm, and also, in the caseof using the resist containing at least one type of solvent selectedfrom propylene glycol monomethyl ether acetate, propylene glycolmonomethyl ether, and methyl isoamyl ketone as the solvent, by settingthe aforementioned rotation speed R2 so as to satisfy the equation,R2=500 to 900 rpm, the mask blank capable of reducing the variations inremoved width in each side of the substrate, and also preventing thedefect caused by the re-adhesion of the dissolved resist could beobtained.

Note that in the aforementioned embodiments, the dissolving step, theremoving step, and the drying step was respectively conducted once.However, as other examples, the dissolving step, the removing step, andthe drying step may be repeated plural times. Processing in the case ofrepeating each step plural times, will be explained with reference toFIG. 6.

FIG. 6 is a graph showing a change in time of the rotation speed of thesubstrate according to the embodiment, where the times are shown on thehorizontal axis, and the rotation speed is shown on the vertical axis.FIG. 6(a) shows a case conducting a series of dissolving step→removingstep→drying step→dissolving step→removing step→drying step, and FIG.6(b) shows a series of dissolving step→removing step dissolvingstep→removing step→drying step.

When each processing is repeated plural times, as shown in FIG. 6(a),the series of steps may be dissolving step→removing step→dryingstep→dissolving step→removing step→drying step, or as shown in FIG.6(b), the series of steps may be dissolving step→removingstep→dissolving step→removing step→drying step, where the drying step isconducted in only the last. When the rotation time T1 (dissolving step),the rotation time T2 (removing step), the rotation time T3 (drying step)of the substrate are repeated plural times, the rotation time indicatestotal rotation time of each step in the unnecessary film removing step.Specifically, in FIG. 6(a), if the series of the steps is dissolvingstep (the rotation speed R1, rotation time T1 a)→removing step (therotation speed R2, rotation time T2 a)→drying step (the rotation speedR3, rotation time T3 a)→dissolving step (the rotation speed R1, rotationtime T1 b)→removing step (the rotation speed R2, rotation time T2b)→drying step (the rotation speed R3, rotation time T3), equations areexpressed by T1=T1 a+T1 b, and T2=T2 a+T2 b. The same thing can be saidfor FIG. 6(b)also. Note that the equation, T3=T3 a+T3 b is established.

By repeating each processing plural times, preferably sectional shape ofthe resist film after removing the unnecessary film becomes good. Notethat if the processing is repeated plural times, preferably theprocessing is repeated 2 to 5 times.

Note that a specific resist is explained as an example in theaforementioned embodiments, however the resist applicable to the presentinvention is not limited thereto. Any resist including thehigh-molecular-weight resist and the chemical amplification resist otherthan the above-described resist may be applied, and whichever ofpositive type or negative type may be applied.

Also, in the aforementioned embodiments, the unnecessary film removingstep was conducted before the heat treatment step. However, if theunnecessary film can be removed by chemical liquid even after heattreatment, the unnecessary film removing step may be conducted after theheat treatment step.

Also, in the aforementioned embodiments, the cover member covering thesurface of the substrate is given as an example. However, the covermember is not limited thereto, and any cover member may be used if afixed gap is formed in the removed area in the main surface of thesubstrate. Also, the cover member may be structured so that a prescribedpart corresponding to a non-removed area of the cover member (which maybe the part corresponding to the entire part of the non-removed area) isopened.

INDUSTRIAL APPLICABILITY

According to a method of manufacturing a mask blank of the presentinvention, the mask blank capable of suppressing the build-ups afterremoving the resist film on the peripheral edge of the substrate andfree of resist residues can be obtained even if using any resist kinds.In addition, even if using any resist kinds, the mask blank capable ofsuppressing the build-ups after removing the resist film on theperipheral edge of the substrate, free of resist residues, furthercapable of suppressing variations in removed width, and capable ofpreventing defects due to re-adhesion of the dissolved resist, can beobtained. Therefore, a transfer mask manufactured by using the maskblank manufactured by this manufacturing method is also capable ofpreventing a defective pattern in an auxiliary pattern formed near theperipheral edge of the substrate.

1. A method of manufacturing a mask blank, comprising: preparing arectangular substrate formed with a thin film becoming a transferpattern to be transferred to a body to be transferred, and also formedwith a resist film by applying resist liquid on the thin film and dryingthe resist film thus applied; removing an unnecessary resist film formedin a removed area provided on a peripheral edge of a main surface of thesubstrate by using chemical liquid; and heating the resist film formedin a non-removed area which is a main surface of the substrate and anarea other than the removed area, wherein in the unnecessary filmremoving step, a cover member is disposed in a main surface of thesubstrate formed with the resist film so as to form a prescribed gapwith a main surface of the substrate in the removed area, further thesubstrate is rotated at the rotation speed R1 to dissolve theunnecessary resist film by feeding the chemical liquid in the gap,thereafter, the feeding of the chemical liquid is stopped, further thesubstrate is rotated at the rotation speed higher than the prescribedrotation speed, and the unnecessary resist film thus dissolved isremoved outside the substrate, wherein the substrate is rotated whenremoving the dissolved unnecessary resist film outside the substrate anddrying the area from which the resist film is removed, at the rotationspeed R2 capable of suppressing variations in removed width in each sideof the substrate, the variation being caused by the difference incentrifugal force applied on the dissolved resist film in a directionalong each side of the peripheral edge of the main surface of thesubstrate, and thereafter, the substrate is rotated at a prescribedrotation speed R3 so as to dry the area from which the resists film isremoved.
 2. The method of manufacturing the mask blank according toclaim 1, wherein the resist liquid contains at least one type of solventselected from the group consisting of diethylene glycol dimethyl ether,anisole, methyl cellosolve acetate, and cyclohexanone as a solvent, andthe rotation speeds R1, R2, and R3 are expressed by:R1=100 to 500 rpm  (I)R2≧300 rpm  (II)R1<R2≦R3.  (III)
 3. The method of manufacturing the mask blank accordingto claim 2, wherein the rotation speed R2 is expressed by R2=300 to 600rpm.
 4. The method of manufacturing the mask blank according to claim 1,wherein the resist liquid contains at least one type of solvent selectedfrom the group consisting of propylene glycol monomethyl ether acetate,propylene glycol monomethyl ether, and methyl isoamyl ketone as asolvent, and the rotation speeds R1, R2, and R3 are expressed by:R1=100 to 500 rpm  (I)R2≧300 rpm  (II)R1<R2≦R3.  (III)
 5. The method of manufacturing the mask blank accordingto claim 4, wherein the rotation speed R2 is expressed by R2=500 to 900rpm.
 6. The method of manufacturing the mask blank according to claim 2,wherein the rotation speed R3 is expressed by R3≧1000 rpm and R3≦3000rpm.
 7. The method of manufacturing the mask blank according to claim 1,wherein the gap is set in a size allowing the chemical liquid to flowinto the gap through the gap and retained only in the gap.
 8. The methodof manufacturing the mask blank according to claim 1, wherein the covermember covers the main surface formed with a larger space than the gapin the non-removed area other than the removed area.
 9. The method ofmanufacturing the mask blank according to claim 1, wherein the chemicalliquid is fed from upside of the cover member to be fed into theunnecessary resist film through a chemical liquid path provided in thecover member.
 10. The method of manufacturing the mask blank accordingto claim 1, wherein the chemical liquid path is defined as a chemicalliquid feeding path for feeding the chemical liquid to a positioncorresponding to the unnecessary resist film portion in the covermember, or as a chemical liquid path between the cover member and achemical liquid guide member by providing the chemical liquid guidemember outside the cover member.
 11. A method of manufacturing atransfer mask, wherein a transfer pattern is formed on the substrate byusing the mask blank obtained by using the method of manufacturing themask blank according to claim 1 and by patterning the thin film.